Roberts Gorden 250 User manual

Brand: Roberts Gorden

Model: 250

Category: Water heaters & boilers

Type: User manual

Installation, Operation

& Service Manual

Models UHA[S]

150, 175, 200, 225

250, 300, 350, 400

P/N 111101 N A 10 /0 7 Rev. D

UHA-Series

Tubular Unit Heaters

(Standard Range)

WARNING

FOR YOUR SAFETY

If you smell gas:

1. Open windows.

2. DO NOT try to light any appliance.

3. DO NOT use electrical switches.

4. DO NOT use any telephone in

your building.

5. Leave the building.

6. Immediately call your local gas

supplier after leaving the building.

Follow the gas suppliers

instructions.

7. If you cannot reach your gas

supplier, call the Fire Department.

Fire Hazard

Do not store or use gasoline or other

flammable vapors and liquids in the

vicinity of this or any other appliance.

Some objects will catch fire or explode

when placed close to heater.

Failure to follow these instructions can

result in death, injury or property

damage.

WARNING

Installation must be done by a contractor qualified

in the installation and service of gas-fired heating

equipment or your gas supplier.

Improper installation, adjustment, alteration, service

or maintenance can result in death, injury or property

damage. Read the Installation, Operation and Service

Manual thoroughly before installing or servicing

this equipment.

Installer

Please take the time to read and understand

these instructions prior to any installation.

Installer must give a copy of this manual to the owner.

Owner

Keep this manual in a safe place in order to provide

your serviceman with necessary information.

Roberts-Gordon, LLC

1250 William Street

P. O . Box 4 4

Buffalo, New York 14240-0044

Telephone: 716.852.4400

Fax: 716.852.0854

Toll Free: 800.828.7450

www.rg-inc.com

Quality in Any Language™

Combat

Roberts-Gordon, LLC

or copied in any form or by any means - graphic, electronic, or mechanical, including

photocopying, recording, taping or information storage and retrieval systems - without the

written permission of Roberts-Gordon, LLC.

Printed in U.S.A.

TABLE OF CONTENTS

SECTION 1: Heater Safety......................................................1

1.1 Manpower Requirements ............................................. 1

SECTION 2: Installer Responsibility ..................................... 2

2.1 Wall Tag ....................................................................... 2

2.2 Corrosive Chemicals.................................................... 2

2.3 National Standards and Applicable Codes ..................2

SECTION 3: Critical Considerations ..................................... 3

3.1 Basic Information......................................................... 3

3.2 Location and Suspension ............................................ 3

3.3 Minimum Required Installation Clearances .................3

3.4 Clearances to Combustibles ........................................3

3.5 Ventilation ....................................................................3

3.6 Gas Supply ..................................................................3

3.7 Electrical Supply .......................................................... 3

3.8 Vent.............................................................................. 3

3.9 Separated Combustion Installation ..............................3

SECTION 4: National Standards and Applicable Codes ..... 5

4.1 Gas Codes................................................................... 5

4.2 Aircraft Hangars ...........................................................5

4.3 Parking Structures and Repair Garages ......................5

4.4 Electrical ......................................................................5

4.5 Venting.........................................................................5

4.6 High Altitude ................................................................ 5

SECTION 5: Major Components ............................................6

5.1 General........................................................................ 6

5.2 Suspension..................................................................6

SECTION 6: Venting................................................................ 7

6.1 Venting.........................................................................7

6.2 Vent Installation ...........................................................7

6.3 Unvented Operation.....................................................8

6.4 Horizontal Venting........................................................ 8

6.5 Vertical Venting............................................................ 8

6.6 Length Requirements .................................................. 8

6.7 Vent Material................................................................ 9

SECTION 7: Air Supply......................................................... 13

7.1 Separated Combustion Installation............................. 13

7.2 Unvented Installation .................................................. 13

7.3 Building Ventilation ..................................................... 13

7.4 Outside Combustion Air Supply.................................. 13

SECTION 8: Gas Piping........................................................ 14

8.1 Connections............................................................... 14

SECTION 9: Wiring................................................................ 15

9.1 Positioning Thermostats ............................................ 15

9.2 Low Voltage Thermostat with One Heater ................. 15

9.3 UHA(S) Series Internal Wiring Diagram .................... 16

9.4 UHA(S) Series Ladder Wiring Diagram ..................... 17

9.5 Electrical Connection to the Heater ........................... 18

SECTION 10: Operation and Maintenance.......................... 19

10.1 Pre-Start-Up Checks................................................ 19

10.2 Begin Start-Up ......................................................... 19

10.3 Complete the Start-Up ............................................. 21

SECTION 11: User Instructions............................................22

11.1 User Instructions.......................................................22

11.2 Heater Operation ......................................................22

11.3 Common User Controls.............................................22

11.4 Lighting Instructions..................................................22

11.5 Simple Troubleshooting.............................................22

SECTION 12: Servicing.........................................................24

12.1 Servicing Instructions...............................................24

12.2 Burner Maintenance.................................................24

12.3 Fan/Motor Assembly Maintenance ...........................24

12.4 Heat Exchanger Maintenance..................................24

12.5 Gas Valve Maintenance ...........................................24

12.6 Combustion Fan .......................................................24

12.7 Venting and Air Intake Pipe ......................................24

12.8 Maintenance Checklist .............................................25

SECTION 13: Troubleshooting .............................................27

13.1 General ....................................................................27

13.2 Troubleshooting For Automatic Ignition Burner

Systems...................................................................28

13.3 Troubleshooting for Flame Supervision System .......29

13.4 Troubleshooting for Gas Valves................................30

13.5 Troubleshooting for Combustion Fan........................30

SECTION 14: Replacement Parts.........................................31

14.1 Gas Valve.................................................................31

14.2 Burner Compartment ...............................................32

14.3 Ignition Electrode and Flame Probe .........................33

14.4 Combustion Fan Vertical Installation ........................34

14.5 Pressure Switch........................................................35

14.6 Ignition Control .........................................................36

14.7 Axial Fan/Guard/Motor Assembly.............................36

14.8 Limit Switches ..........................................................36

SECTION 15: Specifications.................................................37

15.1 Standard (Models 150 - 400) UHA(S) Series

Dimension Data .........................................................37

15.2 General Technical Data Table (All Models) ..............38

15.3 Technical Data Table (All Models) ............................38

SECTION 16: The ROBERTS GORDON

COMBAT

UHA-Series Warranty.....................................39

TABLE OF FIGURES

Figure 1: Installation Clearances and Clearances to

Combustibles.............................................................4

Figure 2: Suspension Methods ................................................. 6

Figure 3: Vent and Roof Detail .................................................. 9

Figure 4: Standard Vented Heater - Vertical and

Horizontal Vent Termination ......................................9

Figure 5: Standard Vented Heater - Common Vertical Vent

Termination.............................................................. 10

Figure 6: Separated Combustion Heater - Vertical and

Horizontal Vent Termination .................................... 11

Figure 7: Concentric Vent Box ................................................ 11

Figure 8: Concentric Vertical and Horizontal Vent

Termination - Separated Combustion Heater........... 12

Figure 9: Gas Connection ....................................................... 14

Figure 10: Automatic Burner Control Sequence......................20

Figure 11: Gas Valve for Models UHA(S) 150 - 400................20

Figure 12: LED Diagnostic Codes........................................... 22

SECTION 1: HEATER SAFETY

Your Safety is Important to Us!

This symbol is used throughout

the manual to notify you of

possible fire, electrical or burn

hazards. Please pay special

attention when reading and

following the warnings in these

sections.

Installation, Service and Annual

Inspection of heater must be done by a contractor

qualified in the installation and service of gas-fired

heating equipment.

Read this manual carefully before installation,

operation or service of this equipment.

Heaters are not approved for residential installation.

These instructions, the layout drawing, local codes

and ordinances and applicable standards that apply

to gas piping, electrical wiring, venting, etc. must be

thoroughly understood before proceeding with the

installation.

Thin sheet metal parts, including the various venting

components, have sharp edges. To prevent injury,

the use of work gloves is recommended.

Before installation, check that the local distribution

conditions, nature of gas and pressure and

adjustment of the appliance are compatible.

1.1 Manpower Requirements

To prevent personal injury and damage to the

heater, two persons will be required for installation.

COMBAT

UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL

SECTION 2: INSTALLER RESPONSIBILITY

The installer is responsible for the following:

• To install the heater, as well as the gas and

electrical supplies, in accordance with applicable

specifications and codes. Roberts-Gordon

recommends the installer contact a Local

Building Inspector or Fire Marshal for guidance.

• To use the information given in a layout drawing

and in the manual together with the cited codes

and regulations to perform the installation.

• To install the heater in accordance with the

clearances to combustibles.

• To furnish all needed materials not furnished as

standard equipment.

• To plan location of supports, vents and air

intakes.

• To provide access for servicing.

• To provide the owner with a copy of this

Installation, Operation and Service Manual.

• To never use heater as support for a ladder or

other access equipment and never hang or

suspend anything from heater.

• To ensure there is adequate air circulation

around the heater and to supply air for

combustion, ventilation and distribution in

accordance with local codes.

2.1 Wall Tag

A laminated wall tag is included with the heater as a

permanent reminder of the safety instructions and

the importance of the required clearances to

combustibles. Affix the tag by peeling off the backing

of the adhesive strips on the rear surface and

position the tag on a wall near the heater.

A copy of the wall tag (P/N 91040031) is illustrated

on the back cover.

Know your model number. Model number is found

on the heater and in the Installation, Operation and

Service Manual.

See Page 9, Figure 3 through Page

14, Figure 9.

2.2 Corrosive Chemicals

CAUTION

Do not use heater in an area containing corrosive

chemicals.

Avoid the use of corrosive chemicals to ensure a

longer life of the burner, heat exchanger and other

parts.

Failure to follow these instructions can result in

property damage.

Roberts-Gordon cannot be responsible for ensuring

that all appropriate safety measures are undertaken

prior to installation; this is entirely the responsibility

of the installer. It is essential that the contractor, the

sub-contractor, or the owner identifies the presence

of combustible materials, corrosive chemicals or

halogenated hydrocarbons* anywhere in the

premises.

* Halogenated Hydrocarbons are a family of chemical

compounds characterized by the presence of halogen ele-

ments (fluorine, chlorine, bromine, etc.). These compounds are

frequently used in refrigerants, cleaning agents, solvents, etc. If

these compounds enter the air supply of the burner, the life

span of the heater components will be greatly reduced. An out-

side air supply must be provided to the burners whenever the

presence of these compounds is suspected. Warranty will be

invalid if the heater is exposed to halogenated hydrocarbons.

2.3 National Standards and Applicable Codes

All appliances must be installed in accordance with

the latest revision of the applicable standards and

national codes. This refers also to the electric, gas

and venting installation. Note: Additional standards

for installations in public garages, aircraft hangars,

etc. may be applicable.

SECTION 3: CRITICAL CONSIDERATIONS

3.1 Basic Information

UHA(S) heaters have automatic ignition burners for

ON/OFF operation only.

3.2 Location and Suspension

All models:

• Must be installed indoors.

• Must be installed in a level position with

horizontal discharge.

• May be mounted on a shelf of non-combustible

material.

• May be suspended from above (See Page 6,

Figure 2) or from wall brackets of sufficient

strength to support the heater as listed in the

Dimension Data Table

on Page 37, Section 15.1.

Drop rods must be a minimum of 3/8" diameter

mild steel. Four suspension points (3/8" nuts)

are located on top of the heater.

• Must be installed in a manner which allows

access to all serviceable components.

See Page 4, Figure 1 for details.

3.3 Minimum Required Installation Clearances

Clearances around the heater and vent must be as

indicated

on Page 4, Figure 1; Page 9, Figure 3

through Page 12, Figure 8 to ensure access for

servicing, and correct operation.

3.4 Clearances to Combustibles

Clearances must be as indicated on Page 4, Figure

1. If clearances to combustibles are not indicated,

then installation clearances apply.

3.5 Ventilation

It is important to ensure that there is adequate air

space around the heater to supply air for

combustion, ventilation and distribution in

accordance with local and national codes.

3.6 Gas Supply

It is important that the gas supply pipe is sized

correctly to provide the inlet pressure as stated on

the heater data plate. The gas supply pipe and

electrical connections must not support any of the

heater's weight.

3.7 Electrical Supply

A permanent 120 V 60 Hz 1 Ø electrical supply is

required for the main electrical power. The heater

also requires suitable controls in accordance with

Section 9.

3.8 Vent

Choose heater orientation to allow for the proper

location of the vent. Each heater must be fitted with

a correctly sized sealed vent system.

If vented horizontally, no other appliance may be

connected to the vent.

See Page 7, Section 6.

3.9 Separated Combustion Installation

For separated combustion installation, the vent and

air intake must be fitted with an individual and

correctly sized sealed system and the vent and air

intake must terminate at approved wall and roof

terminals.

Separated combustion units may not be common

vented.

See Page 7, Section 6.

WARNING

Fire Hazard

Some objects will catch fire or explode when placed

close to heater.

Keep all flammable objects, liquids and vapors the

required clearances to combustibles away from heater.

Failure to follow these instructions can result in death,

injury or property damage.

COMBAT

UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL

Figure 1: Installation Clearances and Clearances to Combustibles

6"**

(15 cm)

31"

(79 cm)

(15 cm)

Clearances to Combustibles

24" for

adequate

air flow access

axial fan.

10'

(3 m)

Wall

Terminal

Roof Terminal

Top

20' (6.0 m) - 30' (9.1 m)

Max. Mounting Height*

Installation Clearances

(Optional separated

combustion concentric

venting shown.)

* Recommended mounting height varies with heater input.

Heaters may be mounted at a higher level if destratification

fans are installed.

Note: Venting directly from top of heater not applicable

on Models 150 - 400.

Clearance to Vent: 2" (5 cm)

**31" (79 cm) minimum is necessary

for servicing.

The heater must always be installed at least 6' (2 m) above the floor.

The vent pipe must have clearance from combustibles by 2" (5 cm).

If installed at low levels where individuals can come in contact with hot heat

exchanger components, adequate guarding must be provided.

SECTION 4: NATIONAL STANDARDS AND APPLICABLE CODES

4.1 Gas Codes

The type of gas appearing on the nameplate

must be the type of gas used. Installation must

comply with national and local codes and

requirements of the local gas company.

United States: Refer to NFPA 54/ANSI Z223.1 -

latest revision, National Fuel Gas Code.

Canada: Refer to CSA B149.1 Natural Gas and

Propane Installation Code.

4.2 Aircraft Hangars

Installation in aircraft hangars must be in

accordance with the following codes:

United States: Refer to Standard for Aircraft

Hangars, NFPA 409 - latest revision.

Canada: Refer to Standard CSA B149.1 Natural

Gas and Propane Installation Code.

• In aircraft storage and servicing areas, heaters

shall be installed at least 10' (3 m) above the

upper surface of wings or of engine enclosures

of the highest aircraft which may be housed in

the hangar. The measurement shall be made

from the wing or engine enclosure (whichever is

higher from the floor) to the bottom of the heater.

• In shops, offices and other sections of aircraft

hangars communicating with aircraft storage or

servicing areas, heaters shall be installed not

less than 8' (2.4 m) above the floor.

• Suspended or elevated heaters shall be so

located in all spaces of aircraft hangars that they

shall not be subject to injury by aircraft, cranes,

movable scaffolding or other objects. Provisions

shall be made to assure accessibility to

suspended heaters for recurrent maintenance

purposes.

4.3 Parking Structures and Repair Garages

Installation in garages must be in accordance

with the following codes:

United States: Standard for Parking Structures

NFPA 88A - latest revision or the Code for Motor

Fuel Dispensing Facilities and Repair Garages,

NFPA 30A - latest revision. Canada: Refer to

CSA B149.1 Natural Gas and Propane

Installation Code.

• In accordance with the Standard for Parking

Structures NFPA 88A, heaters must be located

a minimum of 18" (50 cm) below the floor-ceiling

assembly or 18" (50 cm) above the floor.

• In accordance with the Code for Motor Fuel

Dispensing Facilities and Repair Garages,

NFPA 30A - latest revision, heaters must not be

installed less than 8' (2.4 m) above the floor.

4.4 Electrical

The heater must be electrically grounded in

accordance with the following codes:

United States: Refer to National Electrical

Code

, NFPA 70 - latest revision. Wiring must

conform to the most current National Electrical

Code

, local ordinances and any special

diagrams furnished.

Canada: Refer to Canadian Electrical Code,

CSA C22.1 Part 1 - latest revision.

4.5 Venting

The venting must be installed in accordance

with the requirements within this manual and

the following codes:

United States: Refer to NFPA 54/ANSI Z223.1 -

latest revision, National Fuel Gas Code.

Canada: Refer to CSA B149.1 Natural Gas and

Propane Installation Code.

4.6 High Altitude

These heaters are approved for installations up

to 2000' (610 m) (US), 4500' (1370 m) (Canada)

without modification. Consult factory if US

installation is above 2000' (610 m) or Canadian

installation is above 4500' (1370 m).

COMBAT

UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL

SECTION 5: MAJOR COMPONENTS

5.1 General

Heaters are designed for installation above 6'

(1.8 m). These heaters must be installed within the

heated space. Duct delivery systems are not

permitted with axial fan units. When handling or

supporting the heater from below, ensure that the

weight is taken at the support points.

5.2 Suspension

WARNING

Crush Hazard

Use 3/8" threaded rod

minimum.

Failure of the supports can

result in death, injury

or property damage.

For typical suspension, See Page 6, Figure 2.

Figure 2: Suspension Methods

Cone Point

Set Pin

Window

Clamp

Unistrut

3/8"

Threaded

Rod

Nut

Washer

Riv

Nut

Support Points

Ensure all suspension

hardware is torqued to

a minimum of 20 ft lbs.

Washer

3/8"

Threaded

Rod

Nut

Unistrut

Channel Nut

SECTION 6: VENTING

6.1 Venting

This heater must be vented in accordance with the

rules contained in this manual and with the following

national codes and any state, provincial or local

codes which may apply: United States: Refer to

NFPA 54/ANSI Z223.1 - latest revision, National

Fuel Gas Code; Canada: Refer to CSA B149.1

Natural Gas and Propane Installation Code.

Any portion of vent pipe passing through a

combustible wall must have an listed thimble to

conform with the above codes.

The heater may be installed unvented in

certain circumstances according to building

ventilation codes. Refer to the above codes

and

Page 8, Section 6.3 for further information.

Unvented operation also requires compliance with

the clearances to combustibles given

on Page 4,

Figure 1.

The bottom of the vent or air intake terminal shall not

be located less than 1' (.3 m) above grade level.

The vent shall not terminate less than 7' (2.1 m)

above grade where located adjacent to public

walkways.

Vent terminal must be installed at a height sufficient

to prevent blockage by snow and building materials

protected from degradation by flue gasses.

Vent terminal must be beyond any combustible

overhang.

Secure all joints with corrosion resistant #8 x 3/8"

sheet metal screws.

For single wall venting, pressure sensitive aluminum

tape or silicone sealant must be used to seal all

joints.

Aluminum tape shall have a minimum temperature

rating of 400° F (204° C) and meet SMACNA AFTS-

100-73 standards. High temperature silicone

sealant must have a minimum temperature rating of

480° F (250° C).

6.1.1 United States Requirements

Vent must terminate at least 3' (.9 m) above any

forced air inlet located within 10' (3.1 m).

Vent must terminate at least 4' (1.2 m) below,

4' (1.2 m) horizontally from, or 1' (.3 m) above any

door, operable window, or gravity air inlet into any

building.

NFPA 54/ANSI Z223.1 - latest revision, National

Fuel Gas Code specifies a 4' (1.2 m) horizontal vent

terminal clearance from gas and electric meters,

regulators and relief equipment.

6.1.2 Canadian Requirements

The vent shall not terminate within 6' (1.8 m) of a

mechanical air supply inlet to any building.

The vent shall not terminate within 3' (.9 m) of a

window or door that can be opened in any building,

any non-mechanical air supply inlet to any building,

or of the combustion air inlet of any other appliance.

6.2 Vent Installation

WARNING

Fire Hazard

Some objects will catch fire or explode when placed

close to heater.

Keep all flammable objects, liquids and vapors the

required clearances to combustibles away from heater.

Failure to follow these instructions can result in death,

injury or property damage.

For vented units, the vent must terminate outside of

the building.

Vents must be fully sealed and correctly sized for

the model. If the vent passes through a wall or

ceiling of combustible material, it must be enclosed

by a listed thimble and be separated from the

thimble by at least a 2" (5 cm) air gap.

For separated combustion models, vents and air

intakes must be a fully sealed system and correctly

sized for the model. Vent should be assembled as

detailed

on Page 9, Figure 3 through Page 12,

Figure 8. The joints between the vent terminal and

the roof or wall must be properly sealed. If the vent

passes through a wall or ceiling of combustible

material, it must be enclosed by a listed thimble and

be separated from the thimble by at least a 2" (5 cm)

air gap.

Vents and air intakes must be adequately

supported so that the heater does not bear the

weight of the pipes.

For vent termination See Page 9, Figure 3 through

Page 12, Figure 8.

6.2.1 Standard Vented Heaters

(Models UHA 150 - 400)

The vent must be fitted with a low resistance

terminal.

See Page 9, Figure 3 through Page 9,

Figure 4. Standard vented heaters do not allow

outdoor air intake for combustion air.

COMBAT

UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL

6.2.2 Separated Combustion Heaters

(Models UHAS 150 - 400)

The heaters are designed to be installed as

separated combustion heaters. The vent and air

intake are run as separate pipes to the wall or roof

terminals.

See Page 12, Figure 8. As an option, the

vent and air intake are run as separate pipes to a

concentric vent box and a concentric vent/air intake

pipe penetrates the wall or roof.

6.3 Unvented Operation

Carbon Monoxide Hazard

Heaters installed unvented must

be interlocked with sufficient

building exhaust.

Heaters must be installed

according to the installation

manual.

Failure to follow these

instructions can result in death

or injury.

WARNING

For unvented operation in commercial installations,

sufficient ventilation must be provided in the amount

of 4 cfm per 1000 Btu/h firing rate (United States); 3

cfm per 1000 Btu/h firing rate (Canada).

WA R NI N G: Combustion by-products contain a

chemical known to the State of California to cause

cancer and birth defects or other reproductive

harm.

6.4 Horizontal Venting

Horizontally vented heaters must be individually

vented.

Vent pipe must be sloped ¼" (.6 cm) for every 1' (.3

m). For vent lengths greater than 5' (1.5 m),

condensation will form. Insulation is recommended

and condensation drains may be desired. For vents

pitched up toward the vent terminal, place the

condensation drain within 5' (1.5 m) of the heater.

In noncombustible walls only, vent terminal

(P/N 02537801-1P) may be used.

For 4'' (10 cm) vents in either combustible or

noncombustible walls, use vent terminal (P/N

90502100) or equivalent insulated vent terminal.

Follow the manufacturer's instructions for proper

installation.

Instead of an insulated vent terminal, a listed thimble

(with 2" air gap) may be used with a 4" vent cap (P/N

90502102).

6.5 Vertical Venting

Vertically vented heaters can be common vented

(up to 4 heaters).

For vent lengths greater than 5' (1.5 m),

condensation will form. Insulation is recommended

and condensation drains may be desired. Vent from

the rear of the heater cabinet then run the vent

vertically and use a condensate drain at the bottom

of the vertical vent.

Vent pipe must be sloped 1/4'' (.6 cm) for every

1' (.3 m).

For 4'' (10 cm), an approved vent cap

(P/N 90502102) must be used.

For 6'' (15 cm) common vent, an approved vent cap

(P/N 90502103) must be used.

For common vertical venting of more than two

heaters,

See Page 10, Figure 5.

A vent shall not extend less than 2' (.6m) above the

highest point where it passes through a flat roof of a

building.

6.6 Length Requirements

If using vent lengths greater than 5' (1.5 m),

condensation will form in the vent pipe. Insulation

and additional sealing measures (high temperature

silicone at all seams) are required.

The entire vent should be insulated with foil faced

fiberglass insulation (1/2" thick, 1-1/2# density

minimum).

Maximum Vent Lengths Table

Model UHA(S)

# of Elbows

150 - 400

40 ft (12.2 m) 1

35 ft (10.7 m) 2

30 ft (9.1 m) 3

25 ft (7.6 m) 4

20 ft (6.1 m) 5

SECTION 6: VENTING

6.7 Vent Material

Vent material may be single wall 26 ga. (minimum)

galvanized steel or equal thickness stainless steel.

Completely seal all joints, refer to

Page 7, Section

6.2.

If penetrating a combustible wall or roof, a listed

thimble with 2" (5 cm) clearance must be used.

Where local codes permit, a single section of type

B-1 vent material may be used at the roof or wall

penetration instead of a thimble. Ensure vent

manufacturer's clearance from vent material is

maintained. Seal annular space of the type B-1 vent

as well as all joints in the remaining vent.

Figure 3: Vent and Roof Detail

Roof

Vent

Terminal

Listed Thimble

Flashing

or Rain Collar

Vent

2" Air Gap to

Combustible Material

Figure 4: Standard Vented Heater - Vertical and Horizontal Vent Termination

Vent

Terminal

4" Dia.Vent

Flashing

(By Others)

Listed

Thimble

(2" Clearance)

Vent Terminal

Vertical

Option

Horizontal

Option

Vent

Listed

Thimble

(2" Clearance)

Flashing

(By Others)

12" (31 cm)

Minimum

Condensate

Trap to Drain

(Optional)

Note: Vent supports

not shown.

90°

Bend

Model Vent Diameter Part Number

UHA 150 - 400 4" (10 cm) 90502102

COMBAT

UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL

Figure 5: Standard Vented Heater - Common Vertical Vent Termination

Roof

18" (46 cm)

Min.

Type "B" vent cap

(7" or 8") may be used.

(These are not available

from Roberts-Gordon.)

Roof

Flashing

Approved

Thimble

(If Applicable)

Type "B" Vent Pipe

4" (10 cm)

Single Wall Pipe

4" (10 cm)

Single Wall Pipe

"D" Area must equal sum

of open area of

individual vents.

"D"

Single Wall Pipe

The last section of vent pipe

passing through the roof or

wall may be Type "B" vent pipe.

All other vent materials in the

building must be single wall

vent pipe.

TOP VIEW

SIDE VIEW

SECTION 6: VENTING

Figure 6: Separated Combustion Heater - Vertical and Horizontal Vent Termination

Vent

Termination

Listed Thimble through

Combustible Wall

Vent

12" (31 cm)

Minimum from wall

to vent termination.

Air Intake

Condensate

Trap to Drain

(Optional)

12" (31 cm)

Minimum from air inlet to vent

termination (may be horizontal

or vertical clearance).

Air Intake

Termination

Note: Vent supports not shown

Vent

Air Intake*

12" (31 cm)

Minimum from air inlet to vent

termination (may be horizontal

or vertical clearance).

Vertical

Option

Horizontal

Option

90°

Bend

Model Vent Diameter Terminal P/N

UHAS 150 - 400 4" (10 cm) 90502102

Model *Air Intake Diameter Terminal P/N

UHAS 150 - 250 4" (10 cm) 90502102

UHAS 300 - 400 5" (13 cm) 90502105

Figure 7: Concentric Vent Box

4" (10 cm) Single

Wall Vent Pipe

(By Others)

Seal joint between single wall

and Type B vent with silicone sealant.

Use 3 sheetmetal

screws equally

spaced around joint.

Use 3 sheetmetal

screws equally

spaced around collar.

Concentric

Vent Box

6" (15 cm) or 8" (20 cm)

Single Wall Inlet Air Pipe

(By Others)

One Piece Double Wall Type B-1 Vent Pipe (By Others)

Toward

Heater

Toward

Outside

4" (10 cm) or

5" (13 cm)

COMBAT

UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL

Figure 8: Concentric Vertical and Horizontal Vent Termination

Vent

Air Intake*

Concentric

Vent Box

Vertical

Option

10' (3 m)

Maximum

Horizontal

Option

Concentric

Vent Box

Vent

Combustion

Air Terminal

Vent Terminal

with Baffle Plate

Flashing

(By Others)

Condensate Trap

to Drain (Optional)

4" Type B-1

Vent

Storm Collar (By Others)

(Attach with 3 sheet metal screws.)

UHA 150-250:

6" Dia. Single Wall

UHA 300-400:

8" Dia. Single Wall

Air Intake*

6" (16 cm)

Minimum

12" (31 cm)

Maximum

Combustion

Air Terminal

Vent Terminal

with Baffle Plate

Type

B-1

Vent

Storm Collar (By Others)

(Attach with 3

sheet metal screws.)

Description Part Number Qty.

Concentric Vent Kit (150 - 250) UHVK1

Concentric Vent Box Top & Side Assembly 90504113 1

Concentric Vent Box Bottom Assembly 90504112 1

Screw #6 x 3/8 Self Drilling 91119100 14

4" Vent Terminal with Baffle Plate 90502102R 1

6" Combustion Air Terminal 90502103 1

Description Part Number Qty.

Concentric Vent Kit (300 - 400) UHVK2

Concentric Vent Box Top & Side Assembly 90504013 1

Concentric Vent Box Bottom Assembly 90504012 1

Screw #6 x 3/8 Self Drilling 91119100 14

4" Vent Terminal with Baffle Plate 90502102R 1

8" Combustion Air Terminal 90502104 1

Model Vent Diameter

UHAS 150 - 400 4" (10 cm)

Model *Air Intake Diameter

UHAS 150 - 250 4" (10 cm)

UHAS 300 - 400 5" (13 cm)

- Separated Combustion Heater

SECTION 7: AIR SUPPLY

7.1 Separated Combustion Installation

When installed as a separated combustion heater,

the air for combustion is drawn in from outside the

building. It is important to ensure that there is

adequate space around heater to provide air for the

axial air distribution fan.

7.2 Unvented Installation

It is important to ensure that there is adequate fresh

air supply at all times for both combustion and

heating requirements in accordance with local and

national codes.

WARNING: Combustion by-products contain a

chemical known to the State of California to cause

cancer and birth defects or other reproductive

harm.

7.3 Building Ventilation

Where ventilation is required, air must be taken from

an outside point where it is not likely to be

contaminated or obstructed.

7.4 Outside Combustion Air Supply

If outside combustion air supply is required,

separated combustion model (UHAS) heaters must

be used.

IMPORTANT: If the building has a slight negative

pressure or corrosive contaminants such as

halogenated hydrocarbons are present in the air, an

outside combustion air supply to the heater is

required. Seal all combustion air pipe joints.

The air supply duct may have to be insulated to

prevent condensation on the outer surface. The

outside air terminal must not be more than 1' (31

cm) above the vent terminal.

7.4.1 Length Requirements

Follow the constraints listed on Page 8, Section 6.6.

COMBAT

UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL

SECTION 8: GAS PIPING

WARNING

Fire Hazard

Connect gas supply according to Figure 9.

Gas can leak if not installed properly.

Failure to follow these instructions can result in death,

injury or property damage.

Fire Hazard

Connect gas supply according to Figure 9.

Gas can leak if not installed properly.

Failure to follow these instructions can result in death,

injury or porperty damage.

It is important that the gas supply pipe and the

electrical connections do not support any of the

heater’s weight.

A gas meter is connected to the service pipe by the

gas supply company. An existing meter should be

checked, preferably by the company, to ensure that

the meter is adequate for the rate of gas supply

required.

Installation pipes must be fitted in accordance with

local and national codes. Pipes of smaller size than

the heater inlet gas connection should not be used.

8.1 Connections

Connect the heater to the gas supply ensuring that

the final connections are as follows:

• Gas supply pipe work is run in medium or heavy

gauge tubing in compliance with local and

national codes.

• Meter and service must be large enough to

handle all the burners being installed plus any

other connected load. The gas pipe which feeds

the system must be large enough to supply the

required gas with a maximum pressure drop of

1/2" w.c. When gas piping is not included in the

layout drawing, contact the local gas supplier.

• An isolating valve and union connection should

be used and fitted into the supply adjacent to the

heater.

• A minimum 1/8" NPT plugged tapping

accessible for test connection must be installed

immediately upstream of the gas supply

connection to the heater.

• For suspended heaters, an approved metal

flexible connection between the isolating valve

and the heater may be used. To reduce

pressure loss, use one pipe size larger than

the heater gas connection.

IMPORTANT - The complete installation must be

purged and tested for gas soundness in accordance

with local and national codes.

• Do not high pressure (in excess of 1/2 psi

[14" w.c.]) test the gas piping with the burner

connected. Close manual shut-off valve

during any pressure testing equal to or less

than 1/2 psi (14" w.c.). Failure to follow these

instructions can result in property damage.

Check the pipe and tubing ends for leaks before

placing heating equipment into service. When

checking for gas leaks, use a soap and water

solution; never use an open flame.

Figure 9: Gas Connection

Gas Shut-off Valve

Drip Leg

Cap

Union

Connection

Option B:

Medium or Heavy

Gauge Pipe

Gas Connector

Option A:

Stainless Steel

Flex Gas

Connector

Do not bend flexible

gas connector

sharply.

• Hold gas nipple

securely with pipe

wrench when

attaching the flex gas

connector.

• Do not twist flexible

gas connector.

• Ensure all

joints are

gas tight.

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Roberts Gorden 250 User manual

Brand: Roberts Gorden

Model: 250

Category: Water heaters & boilers

Type: User manual

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Roberts Gorden 250 User manual

Roberts Gorden 250 User manual

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